Patent US2648433A successfully refreshed from Google Patents.
US3772575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High heat dissipation solder-reflow flip chip transistor
Assignee: RCA Corp
•
Filing: 1971-04-28
•
Granted: 1973-11-13
•
Expires: 1991-04-28
Abstract
Abstract An improved method of flip-chip mounting a semiconductor device, such as a transistor, on a pattern of electrical conductors carried on an insulating substrate, comprising providing the device chip with a glass protective layer and on the glass layer metallized bonding pads adjacent to the corners of the chip. Each of the bonding pads includes a relatively wide portion adapted to contain a relatively high mound of solder, and a second portion of a relatively narrow width capable of holding only a thin layer of solder. The thin solder layers overlie heat-generating P-N junction portions of the device. The conductors on the substrate have solder-wettable portions of larger areas than the bonding pads on the chip. Solder balls are placed on the wide portions of the bonding pads and melted to reflow the solder. The chip is then placed face down over the conductors on the substrate and the solder is again reflowed so that the relatively high mounds collapse to the thickness of the thin solder layer portions and the relatively thin solder layer portions are joined directly to the substrate conductors.
Inventors
- 👤 B Hegarty
- 👤 L Trevail
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:41
CPC Classifications
H; H10; H10P; H10P95/00; H10D; H10D99/00; H10W; H10W72/00; H10W72/90; H10W72/071; H10W72/072; H10W72/07231; H10W72/07236; H10W72/20; H10W72/231; H10W72/237; H10W72/241; H10W72/247; H10W72/251; H10W72/29; H10W72/931; H10W72/936; H10W90/00; H10W90/701; H10W90/721; H10W90/724
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
182 words
A semiconductor device adapted to be solder-mounted on metallized areas on an insulating substrate comprising a chip of semiconducting material having a major surface, emitter, base and collector electrode regions within said chip each having a portion extending to and exposed at said chip surface, said emitter region comprising a plurality of isolated portions, widely separated metallized electrode connections on each of said region portions exposed at said chip surface, a thin glass protective layer covering said chip surface and said metallized electrode connections, openings through said glass layer to each of said electrode connections, metallized contact pads on said glass layer each having a first portion of relatively wide dimensions adapted to accommodate a relatively thick, molten free-standing solder layer adjacent the corners of said chip, and each having a narrow second portion adapted to accommodate a relatively thin molten freestanding solder layer, each of said second portions of every pad overlying substantially all of the exposed area of a single isolated emitter region portion of said device, and each of said pads having metal extending through one of said openings.
Claim 2
Dependent Claim
182 words
A semiconductor device adapted to be solder-mounted on metallized areas on an insulating substrate comprising a chip of semiconducting material having a major surface, emitter, base and collector electrode regions within said chip each having a portion extending to and exposed at said chip surface, said emitter region comprising a plurality of isolated portions, widely separated metallized electrode connections on each of said region portions exposed at said chip surface, a thin glass protective layer covering said chip surface and said metallized electrode connections, openings through said glass layer to each of said electrode connections, metallized contact pads on said glass layer each having a first portion of relatively wide dimensions adapted to accommodate a relatively thick, molten free-standing solder layer adjacent the corners of said chip, and each having a narrow second portion adapted to accommodate a relatively thin molten freestanding solder layer, each of said second portions of every pad overlying substantially all of the exposed area of a single isolated emitter region portion of said device, and each of said pads having metal extending through one of said openings.
Claim 3
Dependent Claim
249 words
A transistor adapted to be flip-chip mounted on metallized areas on an insulating substrate, comprising: a generally rectangular shaped chip of semiconducting material having a major surface, said chip having a collector region of one conductivity type having a portion extending to and exposed at said surface at its periphery, a metal electrode connection extending around the periphery of said chip on said exposed portion, a base region of opposite conductivity type within And surrounded by said collector region, said base region also having a portion exposed at said chip surface, a metal electrode connection extending around the periphery of said base region on the exposed portion of said base region, a emitter region of said one conductivity type within and surrounded by said base region, said emitter region comprising a plurality of isolated portions of each of which has a portion exposed at said chip surface, a glass protective layer over said chip surface and over said metal electrode connections, openings through said glass layer to each of said metal electrode connections, metallized contact pads on said glass layer adjacent the corners of said chip, metal from said pads extending through said openings, each of said pads comprising a portion of relatively wide dimensions such that a relatively thick solder layer can be accommodated and a portion of relatively narrow dimensions overlying substantially all of the exposed area of a single isolated emitter portion and each of said narrow portions adapted to accommodate a relatively thin solder layer.
Claim 4
Dependent Claim
249 words
A transistor adapted to be flip-chip mounted on metallized areas on an insulating substrate, comprising: a generally rectangular shaped chip of semiconducting material having a major surface, said chip having a collector region of one conductivity type having a portion extending to and exposed at said surface at its periphery, a metal electrode connection extending around the periphery of said chip on said exposed portion, a base region of opposite conductivity type within And surrounded by said collector region, said base region also having a portion exposed at said chip surface, a metal electrode connection extending around the periphery of said base region on the exposed portion of said base region, a emitter region of said one conductivity type within and surrounded by said base region, said emitter region comprising a plurality of isolated portions of each of which has a portion exposed at said chip surface, a glass protective layer over said chip surface and over said metal electrode connections, openings through said glass layer to each of said metal electrode connections, metallized contact pads on said glass layer adjacent the corners of said chip, metal from said pads extending through said openings, each of said pads comprising a portion of relatively wide dimensions such that a relatively thick solder layer can be accommodated and a portion of relatively narrow dimensions overlying substantially all of the exposed area of a single isolated emitter portion and each of said narrow portions adapted to accommodate a relatively thin solder layer.
References Cited (Backward Citations)
US3226614A
Cited
US3517279A
Cited
US3539882A
Cited
US3567506A
Cited
US3657610A
Cited
US3631307A
Cited
US3697828A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |